Abstract: Cavitation characteristics of filling values on Gezhouba No. 1 Lock prototype is studied. Spectrum analysis technique is used in this paper for the noise data recorded, and much information is drawn including intial and critical state of cavitation, types of cavitation involved, intensity of cavitation, etc. The related phenomena of cavitation and the nature of bottom edge cavitation and top gap cavitation are described. The paper points out that there existed gap cavitation near bottom edge at the beginning of value opening, which was never mentioned before in literatures. In additions, the effect of cavitation on pressure and hoisting load is discoursed. The relation-ship between low frequency noises and vibration of hoisting rods is presented at length in this paper.